As indicated by earlier posts - and Paul Hogan's predicament - tax residency can be a complex issue. Absolute certainty can only be obtained by a private ruling from the ATO. If advice is needed however, I would suggest that pilots should seek it from say one of 'Big 4' accounting firms (or similar specialists) who deal with these issues routinely. They have technical advisors that live and breathe tax residency. I would expect a good employer to seek and pay for such advice on behalf of a group of employees or potential expats....
Although some of the posts have indicated that a whole family needs to relocate on a long term basis to qualify, that is not necessarily the case. The location of your family is only one factor. The way in which a person organises their domestic and economic affairs as part of their lives is a broader, more influential factor. In one private ruling to a pilot a couple of years ago, the ATO noted that his family lived in Australia whilst he was stationed overseas for three years. The ATO has a rule of thumb that two years is the minimum period of time to denote residency of an individual. Maintaining a place of residence in Australia is not the same as actually residing there. A person may have residences in many countries. Notwithstanding continuing ties to Australia, and several visits back to Australia each month, because the pilot's employment ties were in another country and that place was where he carried out the ordinary course of his life, the ATO held that he was considered to be a resident of that place for tax purposes.
As with any private ruling, slighty different facts may well alter the ATO view as they are known to be very fickle....
Hence the need to seek advice specific to your own circumstances.